Abstract: Based on analyzing the thermal effects of pile construction on pile foundation in permafrost regions, the variation laws of radial temperature field and the thermal perturbation radius of pile foundation caused by cement hydration heat are studeied. In view of the transient temperature field equations, nonlinear transient temperature field equations for piles and forzen soil are respectively fomulated. Considering the boundary conditions and freeze-thaw process of transformation, a finite element model of transient temperature field for pile foundation in cold regions is established. The model is employed to simulate the thermal perturbation of pile foundation caused by cement hydration heat. The variation laws of radial temperature field with time at different depths and thermal perturbation regions about 6 times the radius of pile diameter are acquired. The results show that the hydration heat has significant thermal perturbation and long-term effects on the thermal stability of pile foundation. In order to reduce the perturbation, it is essensial to reduce the hydration heat of concrete in permafrost regions.